The invention relates generally to the field of dental instruments, and more particularly, is directed to an improved, precision, endodontic file.
In the preparation of root canals, it is the present practice to enter the chamber of the tooth with a file or reamer to enlarge the root canal. A plurality of endodontic files or reamers of increasing diameter are employed to enlarge the root canal to create a channel of size that can practically be filled with a medicament and then sealed. It is important in the preparation of the root canal to control the length of the file in order to limit the depth of penetration to avoid injury. The current technique for forming this channel to the desired depth usually includes adjusting the length of the file by utilizing an x-ray of the tooth. A simple rubber marker or stopper that is movably positioned on the file has been employed to indicate on the file the depth disclosed by the x-ray. In this manner, when the file enters the root canal, the dentist can limit the depth of file insertion by observing the contact of the rubber marker at the edge of the tooth.
The problems with this prior art procedure are numerous. Firstly, it is difficult for the endodontist to precisely judge when the rubber stopper has reached the end of the tooth. Additionally, the rubber stopper is both flexible and movable and can therefore allow the file to proceed deeper into the root canal then may be actually desired. In other instances, the inadequacies of the equipment result in incomplete penetration. Either too great or too shallow depth penetration could cause failure of the entire procedure. An additional problem is presented in that each individual file and its rubber stopper must be separately gauged against a separate scale or ruler and then individually set to the depth indicated in the x-ray. This procedure can involve inherent inaccuracies and a great deal of time and inconvenience to the dentist. Inaccuracies can also occur because of the number of manual operations involved. Further, problems relating to contamination of the file during this measurement or gauging procedure are likely to occur.
It should be noted that errors in depth penetration of the file or reamer into the root canal, either too deep or too shallow, are the major cause of failure in endodontic procedures. In seeking to overcome such failure, the prior art endodontic instruments have been largely unsuccessful because of complexity or impracticability. Some devices developed by prior workers in the art have included excessive amounts of related paraphernalia or have been inordinately expensive in manufacture. Others have proven impracticable in manufacture or have been deficient in locking the devices or in complexity in calibration. Further, none of the devices currently available offer any assurity of maintaining sterility.